Demand for stretch garments, which apply varying degrees of compressive stretch for sportswear, cosmetic body shaping and medical applications is increasing. In evolutionary terms stretch garment pattern design is in its infancy. Pattern drafting techniques for woven block patterns are well established. Applying these techniques to generate patterns for stretch fabrics can be successful, but it is often at a cost. Using the simplified shapes of modified traditional patterns, proportionately reduced by an arbitrary amount or using smaller sized patterns, can generate garments of dubious fit. All conventional pattern-drafting techniques are based on mathematical formulae that have evolved encompassing an implicit fit rationale. How companies arrived at their approximation of the ideal pattern profile for their particular demographic fit model is usually dependent on the subjectivity and expertise of the designer/technologist fitter. Currently determining the degree of fabric extension and how to apply the amount of available stretch in the pattern reduction process is subjective. Traditional approaches to pattern geometry combined with an arbitrary degree of stretch extension introduces variables at each stage, thus impeding objectivity and the technological evolution of stretch pattern profiling.
Stretch fabrics are produced in a broad range of fibre content and weights with a stretch extension capacity for a variety of applications. Manufacturers of stretch fabric normally use laboratory based electronic testing instruments for the climatically controlled measurement of tensile characteristics. British and American Standard Tests include methods for: fatiguing or ageing specimens; determining extensions at a specific force, modulus, tension decay, residual extension, fatigue set, elastomeric thread break and runback. Fabric and fibre producers and garment technologist use these standard tests to assess the fitness for purpose of a garment fabric and have specific quality assurance parameters in common.
Most manufacturers tend to state a single averaged course/wale stretch for the fabric quality, usually attributed to a range of fabrics but this can be misleading as it is not generally stated that the degree of stretch is obtained by applying differing loads to the individual fabrics This averaged stretch figure is inadequate for stretch pattern design (Ziegert, B. and Keil, G., Clothing and Textiles Research Journal, 1988, 6(4), 54-64).
Information on stretch fabric characteristics and the way stretch extension is quantified in the process of constructing a stretch pattern is not straightforward. To quantify the degree of stretch technical publications for garment pattern construction recommend the hand stretch test method, which is generally agreed to mean ‘the useful limit of extension’. Theoretically it is the point at which the stretched fabric has reached its maximum extension without deforming the hard yarns or fibres (Murden, 1966:356, Elastomeric Thread Review (II): Elastomeric and Fabric Test Method. Textile Institute and Industry, Vol. 4, December, pp. 355-358). Samples of fabric of varying widths different lengths (Haggar, 2004:272, Pattern Cutting for Lingerie, Beachwear and Leisurewear. 2nd Ed., Oxford: BSP Professional Books; Armstrong, H., 1995, Patternmaking for Fashion Design, 2nd Ed., Harper Collins, 471, Murden 1966:356) are pulled until a reasonable resistance to stretch is felt, or until they are visually unacceptable. The degree of extension is then measured on a rule and categorised as low, medium or high stretch. This method of assessing fabric stretch extension is also difficult for the designer/technologist to apply objectively in stretch garment design.
Having first recognised the shortcomings of the present technologies, the problem is to establish a qualitative procedure for measuring, recording and specifying fabric characteristics that would be accessible throughout the clothing and allied industries. This would include fabric manufacturers and distributors, designers/pattern technologists, clothing and allied trades manufacturers and retailers.